whatever's stuck in my head (what's been bugging me), someone important to me, trying to be philosophical, dream, question to something i don't understand
My preference is mostly writing about nature and her allegorical characteristics. I do write haiku, cinquains, clerihew just for fun because the poetry form lends itself to whimsy.
One can write poetry about any subject one wishes too; do not limit thoughts and imagination; do not censure poetic feelings translated on paper.